Your ex, clearly, has issues to work on already with his alcoholism and spending some time in jail likely exacerbated that issue. He has shame surrounding his addiction which I know you are already familiar with due to your daughter. Please tell your children to remember what they are already dealing with with their sister and apply what they’ve learned here too. Al-Anon can help a lot. Their fathers problems aren’t theirs, but they can learn to live with what is going on. Hugs.